Governor mechanism



June 18, 1940. E. E. WOODWARD GOVERNOR MECHANISM 2 Sheets-Sheet 1 Filed March 1, 1935 June 18, 1940. WQQDWARD 2,204,640

GOVERNOR MECHANISM Patented June 18, 1940 covaanoa MECHANISM Elmer E. Woodward, Rockford, 111., asslgnor to Woodward Governor Company, Rockford, 111., a corporation of Illinois Application March 1, 1935, Serial No. 8,908

17 Claims.

This invention relates to governors of the hydraulic type and the general object is to provide such a governor which is simple in construction, easy to adjust while in operation, and capable of responding more quickly to speed changes and correcting such changes more rapidly than prior governors of the same type.

Another object of the invention is to provide a novel form of governor control mechanism in which the static friction between the parts'is minimized and in which the operating characteristics are improved in other respects so that the device responds quickly and accurately.

Still another object of the invention is to provide a governor control mechanism of such character that its speed setting adjustment may be readily manipulated while the device is in operation despite the inclusion in the mechanism of relatively rotatable fluid control valve elements which valve elements are maintained in constant relative rotation during the operation of the" device.

The invention also resides in various structural improvements in governor control mechanisms by means of which accurate and precise governor operation is achieved in an extremely compact, simple and rugged construction.

The invention is illustrated in the accompanying drawings in which-- Figurel is a hydraulic circuit of the automatic governor control showing everything more or less diagrammatically;

Fig. 2 is a longitudinal section through the governor unit;

Fig. 3 is a horizontal cross-section on the line 3-3 of Fig. 2;

' Figs. 4 and 5 are sectional details in vertical planes on the correspondingly numbered lines of Fig. 2, and

Figs. 6 and '7 are horizontal sections in the same plane, Fig. .6 looking down upon the seat on the engine block for the governor unit, and Fig. 7 looking up at the bottom of said unit.

The governor constituting the present invention is particularly adapted to meet the exacting requirements of an automatic mechanism for adjusting the pitch of an airplane propeller.

Accordingly, the invention has been shown and will be described herein as applied to such use. It is to be understood, however, that I do not intend to limit the invention by such disclosure but aim to cover all modifications and alternative constructions falling within the spirit and scope of the invention.

Referring to Fig. 1, a propeller pitch adjustment mechanism has been shown in which 8 is the crank shaft on the forward end of which a piston 9 is mounted, received in a working cylinder l0 arranged to reciprocate relative to the piston. Forward movement of the cylinder is secured by supplying oil under pressure through the passage I I provided in the crank shaft extendcounterweights being moved inwardly toward the crank shaft axis. Contrariwise, when oil is allowed to escape from the cylinder l0 through the passage II so that the cylinder I0 is free to move rearwardly, the counterweights l5 move outwardly away from the crank shaft axis under centrifugal force and accordingly cause the blades I6 to move to a higher pitch position.

In applying the present governor to the control of the pitch of a propeller, the flow of pressure fluid to and from the servo cylinder is controlled by an automatically operable valve H, the position of which is controlled by a fly-ball governor i8, whereby in the speeding up or slowing down of the engine the governor valve produces automatically the required change in propeller pitch, so as to maintain substantially constant speed. The governor is suitably driven in proportion to the engine speed. In this case I9 is the drive shaft for the governor l8, driven, as

indicated at Illa and 20, directly off the crank 3 shaft 8. 2| is a gear pump, the driving-shaft 8a of which may be an extension of the crank shaft 8 or a jack-shaft driven thereby, so that the pump 2| is driven continuously in the operation of the engine. This pump is the engine lubri-- eating pump and draws oil from the sump 22 through a pipe 23 and delivers it at a substantiallyv constant pressure through a pipe 24 to the bearings to be lubricated, a constant pressure of say 85 lbs. being assured by the pressure relief 5 valve 25 arranged to discharge into the sump 22, as indicated. 26 is another gear pump whose .driving shaft is the shaft l9 previously mentioned, the pump 26 being shown turned through 90,into the plane of the shaft Is for the sake of a clearer understanding of the operation, this being a diagrammatic view. The pump 26 will hereafter be referred to as the booster pump to distinguish it from the ehgine lubricating pump 2| and because it is supplied with oil, as at 21,

under the lower pressure delivered from-the pump 2| and in turn delivers the oil under a higher pressure of say 115 lbs. through passage 291 to the governor valve H. A constant pressure is maintained on the discharge side of the pump 26 by a pressure relief valve 29 arranged to discharge, as at 36, back into the intake of the pump 26.

Referring to Fig. 2, the governor valve |1 comprises a body 3| formed as a boss cast integral with the bottom of the cup-shaped housing 32 of the governor l8. The boss 3| is also recessed at the bottom, as at 33, to provide cavities for the reception of the intermeshing gears 34' and 35 of the booster pump 26. The gear 34 is keyed or otherwise fixed to the shaft I9 to turn therewith and communicate rotation to its companion gear 35. A face plate 36 dowelled to the bottom of the boss 3|, as at 31 (Fig, '7), closes the gear cavities and is fastened in place suitably by a single screw 38 to complete the governor unit assembly. This unit embodying the governor l6,

valve I1, and booster pump 26, is arranged to be demountably secured upon a seat 39 provided therefor' on a convenient part 46 of the engine block. Four cap screws 4| serve to fasten the unit in place so that the hexagonal end 42 of the shaft I9 is coupled to the engine driven shaft I912 by entry in the hexagonal bore 43 formed in the latter, and so that ports 44 and 45 in the seat 39 communicating with a passage 21 extending from the engine lubricating pump 2| will communicate with ports 44a and 45a, respectively, provided in the face plate 36, and, at the same time, another port 46 provided in the seat 39 and communicating with a passage 41 leading to the collector ring |2 will be placed in communication with a port 46a in the face plate 36. The port 4411, as appears in Fig. 4, is interconnected with a port 441) through a passage 48 in the face plate 36, and there are two ports 46a and 481) at opposite ends of this passage opening to, the top surface of the face plate. A plug 49 closes the port 46b. The port 48a communicates with a passage 56 on one side of the pump gears 34-35 which would communicate with a transverse passage 5| were it not for the plug 52 which cuts off such communication. However, another passage 53 on the other side of the pump gears communicates with the passage 5|. The latter has a transverse pressure port 54 extending in opposite directions therefrom for communication with an external annular groove 55 in the shaft l9 and also with the pressure relief valve 29. The shaft i9 has a longitudinal bore 56 in which the stem or plunger 51 of the governor valve I1 is reciprocable, and there are radial holes 59 establishing communication between the bore 56 and the groove 55, as shown. From this description, it should be clear that oil under the lower pressure delivered from the pump 2| through passage 21 is conducted through ports 44 and 44a to the passage 49 in the face plate 36, and fromthere through port 48a into passage 56 on one side of the pumping gears. The booster pump delivers the oil under higher pressure to the passage 53, from where it is conducted through passage 5| and port 54 to the valve l1. Now, a tubular stub shaft 59 is received in registering bores in the boss 3| and face plate 36, and provides a passage 36 arranged to communicate with the pressure port 54 when the relief valve 29 opens against the action of its spring 66. The passage 36 communicates with a port 36' in the bottom of the face plate 36, which, as shown in Fig. 7, communicates with the port 45a, previously mentioned, as well as with another port 45b. Hence, when the relief valve opens, oil

pump 26. Reciprocal ports are provided, numbered, 44b, 45b and 46!), so as to permit easily converting the booster pump from right to left hand operation, or vice versa. The booster pump is illustrated in Fig, 4 with the parts thereof arranged for left-hand rotation of the shaft l9,

the plug 49 being inserted in port 48b and the plug 52 closing the top of passage. 56. However, for right-hand rotation of the shaft l9, one must transfer the plugs 49 and 52 so as to close the port 43a instead of 48b, and close the upper end of passage 53 instead of passage 56. The plug 52 is interchangeable with the plug 52. The interchangeability of the pump aiforded by reciprocal ports also necessitates the provision of a reciprocal port 4617 for the port 46a, because, in a reversedarrangement, the passages 21 and 41 (Fig. 6) would, of course, be reversed from the relationship shown. The ports 46a and 46b both communicate with a discharge passage 6| communicating with an annular groove 62 in the passage IS. The groove communicates with the bore 56 through radial holes 63, whereby to establish communication between the governor valve l1 and the passage 6|.

The plunger 51- of the governor valve H is annularly reduced-at a and b and has the portions 0 and d fitting with a close working fit in the bore' 56, and the end portion e sufficiently reduced to leave an annular space around it for free passage of oil through the bore and out to the sump 22 directly through the open end 56 of the bore and also through a radial hole 64 communicating with the annular space 65 in the seat 39 from which oil is drained to the sump through another hole 66. The lands 0 and (1 having the same annular area exposed to the pressure of the oil from port 54, it is manifest that the valve plunger 51 is balanced and can therefore be moved easily by the governor. Upward movement, as will presently appear, goes with increased engine speed, and, in that event, the holes 63 are uncovered more or less according to the extent of movement of the plunger 51'. Oil will, therefore, escape from the passage 6| through the bore 56 to the sump. This oil comes from the working cylinder l6 of thecontrollable pitch propeller,.as follows; through the passage II to the collectorring I2, and thence through passage 41 to the port 46 and through registering port 46a to passage 6|, and thence through annular groove 62 and holes 63 to the bore 56, and thence to the sump 22. The oil is forced out of the cylinder under the action of the centrifugal weights l5 which simultaneously turn the blades |6 to a position of greater pitch. On the other hand, the plunger 51 is given downward movement in the event of decreased engine speed, and, under those conditions, oil under pressure from the port 54 is delivered through the holes 63 and annular groove 62 to the passage 6| and finds its way-through the circuit just outlined to the cylinder I6, and moves said cylinder outwardly against the action of the counterweights l5 and changes the blades l6 to a position of less pitch.

The governor l9 has its cup-shaped housing 32 closed by a cover 61. Weights or fly-balls 68 are revolved in the housing 32 with a head v69 that is fixed on the upper end of the shaft I9 ated by the pilot in the cockpit, or pilot's comso that the latter serves to drive the governor as well as constituting'bne element of the valve II. The weights are pivoted, as at 10, on said head. A coiled compression spring 1| acts normallyto urge the'plunger 51 of the valve l1 downwardly and at the same time force the weights 58 inwardly, but the weights are arranged to move outwardly under centrifugal force against the action of the spring to move the plunger 51 upwardly. A ball bearing 12 is carried'on the up-, per end of the plunger 51 with its inner race clamped to the plunger by a nut 18, which at the same time provides a seat 14 for the lower end of the spring 1|. The weights 68 have fingers 15 which bear against the outer race of the bearing 12. With this construction it is obvious that the head 69 and weights 88 are free to revolve relative to the plunger 51 and spring 1|, and that the plunger will move upwardly against the action of the spring 1| when the weights are thrown outwardly under centrifugal force with increased engine speed. The outward movement of the weights is limited by the engagement of projections 16 on the pivot portions of the weights with the head 59, so that the weights will not come into contact with the side wall of the housing 82.

The cover 51 has a hollow cylindrical boss 11 in which a plunger 18, hearing on the upper end of the spring 1 I, is slidable. The plunger has rack teeth 19 formed in one side thereof, and a pinion 88 meshes with said rack and is arranged to be turned by means of a lever 8i oscillated manually through a suitable push-pull cable (not shown) connected with a knob or control lever operpartment. Depression of the plunger 18 obviously increases the spring pressure upon the plunger 51 so that a higher engine speed is required to move the weights 68 outwardly to bring the plunger 51 to a given position, and vice versa. This control furthermore enables the pilot to move the plunger 51 downwardly positively in the event the spring 1| does not exert sufficient pressure to overcome a tendency on the part of the plunger to stick or bind in the bore 56. A pin 82, extending through the plunger 18, has heads 83 and 84 at its opposite ends, the head 84 being received in a chamber in the nut 13 on the upper end of the plunger 51. This headed pin does not interfere in any way with depression of the plunger 18 or raising thereof to a certain limit, but serves to provide a positive connection between the plunger 18 and the plunger 51 to enable the pilot to positively raise the plunger in the event it sticks and the weights 68 fall to move the same. is apparent, therefore, that while the governor serves to automatically operate the valve l1, the pilot can at any time adjust the governor manually to change to a higher or lower critical engine speed, and in the event of a mechanical trouble arising in the governor, the pilot can manipulate the valve l1 by hand in either direction. Any oil leaking along the plunger 51 and shaft I9 upwardly into the housing 32 is drained through the holes 85 and 85 into the'recess 55 and thence through holes 66 to the sump.

In operation, when the engine is started, the weights 68 turn at such a slow speed that the passage BI is in open communication with the passage 5| so that oil under pressure will be supplied to the working cylinder ID to decrease the pitch of the propeller. In that way, since the load is lessened, the engine will speed up,

and the engine promptly attains a desired speed. As the engine speeds up, the weights 68 move outwardly under centrifugal force and raise the plunger 51 of the governor valve l1 so, as to close the holes 53 and cut off communication with the source of oil pressureat the same time sealing the working cylinder against loss of oil, whereby to maintain the pitch adjustments The pitch adjustment remains the same so long as the load on the engine is balanced against the power output of the engine and the speed remains uniform at a given throttle setting. The aim is to keep the engine turning at a constant speed nearest its rated R. P. M. and power output- That speed, which may be referred to as the critical speed, depends upon the pressure exerted by the spring 1Iwlth a light spring pressure which permits the weights 88 to move outwardly under centrifugal force more readily than with a heavy spring pressure, a lower critical speed will be maintained, and contrariwise with heavier spring pressure a higher critical speed will be maintained. Thepilot can adjust the spring pressure to suit conditions by merely manipulating the lever 8i. Ordinarily the spring pressure will be increased for take-off purposes, because, under those circumstances, or for that matter in any steady climb, the engine should be operated at a speed at or somewhat above its rated R. P. M. for best efficiency. On the other hand, the spring pressure may be lessened for cruising, because then the engine will ordinarily be operated at or somewhat below its rated R. P. M. The adjustment of the lever 8| by push-pull cable control from the cock-pit can be attended to by the pilot very easily. This same control serves as a safety, inasmuch as it enables the pilot to positively operate the governor valve l1 one way or the other in the event the governor weights 68 fall to move the plunger 51 upwardly, or the spring 1! fails to move the plunger downwardly. In other words, the automatic control can, at will, be converted into a manual control, so that there is nothing which could possibly mean a hazard for the pilot in the operation of his ship. When the ship is in flight, the governor valve will move up and down repeatedly as increases and decreases of engine speed must be checked. If, due to a change in altitude of the ship, let us say into a dive, the load upon the engine is decreased and it accordingly tends to speed up, the weights 68 move outwardly and raise the plunger 51 to allow oil to escape from the working cylinder ill. The counterweights l5 thereupon immediately move the blades l6 to a position of increased pitch and the speedof the engine is promptly brought back to normal. The plunger 51 quickly resumes its position covering the holes 63 when the speed of the engine gets back to normal, so that the new pitch adjustment is maintained because the working cylinder i0 is sealed. The engine cannot under any circum-- stances, therefore, have excessive speeding, as would otherwise occur in a dive. On the other hand, when the ship levels off again so that the load upon the engine is increased, there is a decrease in engine speed momentarily, and the movement inwardly of the weights 68 allows the spring 1| to move the plunger 51 downwardly to place the holes 63 in communication with the pressure port 54, so that oil is supplied under pressure to the cylinder ill so as to decrease the propeller pitch and allow the engine to regain its normal speed. Here again, the plunger 51 -promptly returns to its position covering the holes 63 to seal the working cylinder and maintain the propeller pitch adjustment. If the ship then goes into a climb so that the load upon the engine is further increased, it follows that a further automatic adjustment of the propeller pitch will occur and the engine will be allowed to operate at .its normal speed. In a multi-motored ship, where the failure of one engine imposes greater load upon the other engine or engines, the slowing down results in an automatic change in pitch adjustment similarly as just described, and the other engine, or engines, are not overloaded. Under all circumstances, each engine is operated at its peak efficiencyturning constantly at its rated R. P. M. with its propeller pitch always adjusted so that the load balances the power output.

The governor above described is extremely sensitive to speed changes and operates rapidly to correct for such changes by adjusting the speed regulator-which in this instance is the propeller adjusting mechanism. This improved action is due to the substantial elimination of static fric-.

tion between the relatively moving parts of the valve IT. This is accomplished by rotation of the ported sleeve l9 thereby eliminating static friction between this sleeve and the plunger 51. The latter and the speeder spring II are not rotatable owing to the fact that there is'greater torsional friction between the spring and the adjusting rack 18 than there is in the parts of the ball thrust bearing 12. As a result, no friction is introduced as an incident to provision for manual adjustment of the speeder spring while the governor is in operation so that the plunger 5'! is freely shiftable in response to changes in the positions of the flyweights, the governor being thereby rendered very sensitive.

I claim:

1. A governor control mechanism comprising a valve chamber, rotatable fiyweights, a hollow shaft rotatable with said flyweights and extending into said chamber and having spaced ports therein, a normally non-rotatable valve stem disposed in said shaft and controlling said ports by relative reciprocation between the stem and said shaft, a fluid servo motor, a conduit between said valve chamber and said motor, and other conduits between said valve chamber and a source of pressure fiuid'supply and a drain receptacle.

2. A governor control mechanism, comprising a valve chamber, a hollow drive shaft extending through said chamber and having spaced valve ports therein, a valve stem reciprocable in. said hollow drive shaft, a coiled governor spring bear= ing on one end thereof tending normally to move it in one direction relative to the ports while holding it against rotation with said shaft,'governor flyweights turning with said shaft relative to' said stem and spring adapted to move the stem in the other direction relative to the ports, a fluid motor, a conduit between said valve chamber and said motor, and other conduits between said valve chamber and a source of pressure fluid supply and a drain receptacle.

3. A governor control mechanism, comprising a valve chamber, a hollow drive shaft extending through said chamber and having spaced valve ports therein, a valve stem reciprocable in said hollow drive shaft, a coiled governor spring hearing on one end thereof tending normally to move it in one direction relative to the ports while holding it against rotation with said shaft, govthe stem in the other direction relative to the ports, manually adjustable means for adjusting said spring while holding it and the stem against turning, a fluid motor, a conduit between said valve chamber and said motor, and other conduits between said valve chamber and a source of pressure fluid supply and a drain receptacle.

4. A governor control mechanism, comprising a body having a chambered portion, a hollow shaft rotatably mounted in a bore provided in said body communicating with the chambered portion, governor mechanism in said chambered portion including fly-weights pivotally mounted on the end of said shaft and spring means non-rotatably mounted relative to said shaft and weights and normally tending to move said weights to a retracted position, said shaft being arranged to be driven in timed relation with the member the speed of which is to be governed, and a control valve plunger reciprocable in said shaft but held against turning therewith and operatively connected with the governor mechanism for movement back and forth in accordance with speed changes, said body having fluid passages therein communicating with the bore for inlet and outlet of fluid to said valve, and said shaft having openof which is concentric with the driven shaft,

intermeshing pumping gears disposed in said recesses one of which is driven by said shaft, the other being an idler, a face plate detachably secured to the body closing the gear recesses, a hollow stub shaft in said body concentric with the idler gear recess and rotatably supporting the idler gear, said body and face plate having bypasspassages communicating with the bore of said stub shaft and with the discharge side of the pumping gears, and a pressure relief valve controlling the flow of fluid through said by-pass.

6. A governor unit comprising fly-balls rotated in unison with a member the speed of which is to be regulated, a tubular ported valve body turning with said fly-balls arranged to have the ports thereof communicate with the working cylinder and also with the source of pressure fluid supply and a drain, a single plunger valve reciprocable within but non-rotatable with the ported body and arranged in one position to trap the fluid in the working cylinder but when moved in one direction to cause fluid injection into the cylinder and when moved in the other direction to cause drainage of fluid from said cylinder, spring means for restraining the fly-balls, and

means operatively connecting the plunger valve to the fly-balls and spring means so as to have the plunger valve moved positively in one direction by the fly-balls and impositively in the other direction by the spring means, and. further so as to cause the plunger valve and spring means to remain stationary with respect to the relatively rotating fly-balls and valve body.

7. In a governor controlled valve for regulating a hydraulic mechanism, centrifugally actuated members, a hollow drive shaft for said centrifugally actuated members having spaced ports therein, a valve stem 'slidable in but non-rotat ing a hydraulic mechanism, a casing having a governor chamber, a valve chamber, a pump chamber, and a pressure relief device chamber therein and channels leading from the exterior of said casing to said pump chamber, from said pump chamber to said valve chamber, and from said valve chamber to said pressure relief device chamber, a governor in said governor chamber, a hollow drive shaft for said governor extending through said pump chamber and said valve chamber having spaced valve ports therein, a valve stem in said hollow drive shaft operatively connected with said governor for controlling said valve ports, a pump gear on said drive shaft in said pump chamber, a spur gear in said pump chamber meshing with said pump gear, a tubular bearing pin for said spur gear extending at one end into said relief device chamber and hydraulically connected at its opposite end with said channel leading from the exterior of said casing to said pump chamber, a spring tensioned pressure relief device in said pressure relief device chamber for controlling the flow of fluid from said valve chamber. through said pressure relief device chamber and said hollow bearing pin back to said pump, means connecting said pump chamber with a source of fluid under initial pressure, and a conduit between said valve chamberand said hydraulic mechanism.

9. In a governor controlled valve for regulating a hydraulic mechanism, a casing having a governor chamber, a valve chamber, a pump chamber, and a pressure relief device chamber therein, and channels leading from the exterior of said casing to the pump chamber from the pump chamber to the valve chamber and from the valve chamber to the pressure relief device chamber, a governor in the governor chamber, a hollow drive shaft for the governor extending through the pump chamber and valve chamber having spaced valve ports therein, a valve stem in said hollow drive shaft operatively connected with the governor for controlling said valve ports, a pump gear on the drive shaft in the pump chamber, a

spur gear in the pump chamber meshing with the the pressure relief device chamber and said hollow bearing pin back to said pump.

10. In a governor controlled valve for regulating a hydraulic mechanism, a casing having a governor chamber, a valve chamber and a pump chamber therein, and channels leading from the exterior of said casing to the pump chamber and from the pump chamber to the valve chamber, a governor in the governor chamber, a hollow drive shaft for the governor extending through the pump chamber and valve chamber having spaced valve ports therein, a valve stem in said hollow drive shaft operatively connected with the governor for controlling said valve ports, a pump gear on the drive shaft in the pump chamber, a spur gear in the pump chamber meshing with the -pump gear, a tubular bearing pin for the spur gear providing a channel for fluid flow therethrough from the valve chamber back to the .pump, and a pressure relief device for controlling fluid flow through said channel.

' 11. A governor mechanism comprising, in combination, a flyball head having flyball weights movably mounted thereon, a rotatable hollow drive shaft coupled to said flyball head in driving relation therewith, said hollow shaft having a port therein, means for supplying pressure fluid to the ported portion of said shaft, a valve plunger telescope within said shaft and reciprocable therein to control said port, said plunger being normally non-rotatable, and means for operatively connecting said flyball weights to said plunger to shift the same axially in response to changes in the speed of rotation of said drive shaft.

12. A governor mechanism comprising, in combination, a flyball head having flyball weights movably mounted thereon, a rotatable hollow drive shaft coupled to said flyball head in driving relation therewith, said hollow shaft having a port therein, means for supplying pressure fluid to the ported portion of said shaft, a normally non-rotatable valve plunger telescoped bell cranks for pivotally supporting said weights Y on said head with an arm of each of said bell cranks extending radially inward toward the axis of rotation of said head, a hollow tubular drive shaft coupled to said rotatable head in driving relation therewith, said shaft having a port therein, means for supplying pressure fluid to the ported portion of said shaft, a valve plunger telescoped within said shaft and reciprocable therein to control said port, a thrust bearing including opposed races with anti-friction ele-,

ments therebetween, one of said races being movable with said plunger and the other carried" by said radially extendingbell crank arms for operatively connecting said flyball weights and plunger, and a helical compression spring coaxial with said plunger and connected to one end thereof for yieldably urging the same axially in one direction, said spring and plunger being held against rotation during normal operation of the governor.

l4. A'governor mechanism comprising, in combination, a pair of relatively rotatable-fluid-control valve elements including a ported sleeve element and a plunger element telescoped therein, a rotatable flyball head connected to a rotatable one of said relatively rotatable valve elements for rotation therewith, means including a flyball weight carried by said head and operatively connected to the other of said valve elements for shifting the same axially with respect to one of said valve elements, means including a speeder spring yieldably urging said other valve element axially in one direction, and non-rotatable means acting on said spring and manipulable during relative rotation of said valve elements for adjusting said spring to vary the force: exerted thereby on said other valve element.

15. In a governor mechanism for regulating a hydraulic device the combination of, a casing having a pump chamber, a drive shaft journaled in said casing and passing through said plump chamber, a governor connected in driven relation with said shaft, a fluid control valve operatively connected to said governor, a pump in said chamber" embodying a pump gear on said drive shaft and spur gear in said pump chamber meshing with the pump gear, a stub shaft for said spur gear having a passage extending axially therethrough and communicating at its opposite ends with the inlet and outlet sides of said pump, and a pressure'relief device for controlling the flow of fluid from said outlet side of said pump through said passage to the inlet side of said pump.

16. A governor mechanism comprising, 'in combination, a pair of relatively rotatable fluid-control valve elements including a ported sleeve element and a plunger element telescoped therein,

a flyball head rotatable with one of said valve elements, a flyball carried by said head and 0peratively connected to one of said valve elements for shifting the same axially with respect to the other element in response to changes in the speed of the rotatable element, a speeder spring coiled about the axis of said elements and yieldably urging said axially movable valve element axially in one direction, and non-rotatable means acting on said spring and manipulable during relative rotation of said valve elements for adjusting said spring to vary the speed controlling force exerted thereby.

17. A governormechanism having, in combination, a rotatable hollow drive shaft rotatable with the part whose motion is to be regulated and having valve ports therein, a flyball head rotatable with said shaft and carried by one end thereof, a normally non-rotatable valve stem reciprocable in said shaft and coacting therewith to constitute a valve, one end of said plunger projecting from said shaft through said flyball head, an antifriction bearing having opposed race members, one actuated by said flyballs and the other coupled to said plunger, a non-rotatable speeder spring coiled about the axis of said plunger and disposed on the side of said head opposite said shaft with one end coupled to said plunger to urge the latter in one direction against the action of said flyballs, and means manipulable while said shaft is rotating and acting on the opposite end of said spring to adjust the force exerted thereby on said plunger.

ELMER E. WOODWARD. 

